title: CpG dinucleotide-specific hypermethylation of the TNS3 gene promoter in human renal cell carcinoma.
abstract: Tensin3 is a cytoskeletal regulatory protein that inhibits cell motility. Downregulation of the gene encoding Tensin3 (TNS3) in human renal cell carcinoma (RCC) may contribute to cancer cell metastatic behavior. We speculated that epigenetic mechanisms, e.g., gene promoter hypermethylation, might account for TNS3 downregulation. In this study, we identified and validated a TNS3 gene promoter containing a CpG island, and quantified the methylation level within this region in RCC. Using a luciferase reporter assay we demonstrated a functional minimal promoter activity for a 500-bp sequence within the TNS3 CpG island. Pyrosequencing enabled quantitative determination of DNA methylation of each CpG dinucleotide (a total of 43) in the TNS3 gene promoter. Across the entire analyzed CpG stretch, RCC DNA showed a higher methylation level than both non-tumor kidney DNA and normal control DNA. Out of all the CpGs analyzed, two CpG dinucleotides, specifically position 2 and 8, showed the most pronounced increases in methylation levels in tumor samples. Furthermore, CpG-specific higher methylation levels were correlated with lower TNS3 gene expression levels in RCC samples. In addition, pharmacological demethylation treatment of cultured kidney cells caused a 3-fold upregulation of Tensin3 expression. In conclusion, these results reveal a differential methylation pattern in the TNS3 promoter occurring in human RCC, suggesting an epigenetic mechanism for aberrant Tensin downregulation in human kidney cancer.
authors.affiliation: Institute of Biomedical and Biomolecular Science (IBBS), School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Carter
authors.forename: Dariusz C
authors.initials: DC
authors.lastname: Górecki
authors.forename: Charles A
authors.initials: CA
authors.lastname: Mein
authors.forename: Börje
authors.initials: B
authors.lastname: Ljungberg
authors.forename: Sassan
authors.initials: S
authors.lastname: Hafizi
mesh_terms: D001374:Azacitidine / Q000494:pharmacology; D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D016022:Case-Control Studies; D019295:Computational Biology; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D005091:Exons / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D007680:Kidney Neoplasms / Q000235:genetics*; D008840:Microfilament Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D000070876:Tensins
chemical_list: D008840:Microfilament Proteins; C000603370:TNS3 protein, human; D000070876:Tensins; D001374:Azacitidine
keywords: DNA methylation; Tensin3; metastasis; pyrosequencing; renal cell carcinoma